Which of the curve shows, how oxygen is loaded and unloaded due to partial pressure?

Options

A. `O_2` curve
B. `CO_(2)` Curve
C. Bohr's curve
D. `O_2` Dissociation curve

Answer

To solve the question regarding which curve shows how oxygen is loaded and unloaded due to partial pressure, we can follow these steps:

### Step 1: Understand the Context
We need to identify the curve that represents the relationship between the partial pressure of oxygen (pO2) and the saturation of hemoglobin with oxygen (oxyhemoglobin saturation).

**Hint:** Think about how oxygen binds to hemoglobin and how this process is influenced by the concentration of oxygen.

### Step 2: Identify the Relevant Curves
The question mentions several curves:
- O2 curve
- CO2 curve
- Bohr curve
- O2 dissociation curve

**Hint:** Recall what each curve represents. The O2 dissociation curve specifically relates to oxygen and hemoglobin.

### Step 3: Focus on the O2 Dissociation Curve
The O2 dissociation curve plots the percentage saturation of hemoglobin with oxygen against the partial pressure of oxygen. This curve is typically S-shaped (sigmoidal) due to the cooperative binding of oxygen to hemoglobin.

**Hint:** Consider why the curve is S-shaped. It involves the cooperative nature of hemoglobin's binding to oxygen.

### Step 4: Analyze the Characteristics of the Curve
The S-shape of the O2 dissociation curve indicates that as the partial pressure of oxygen increases, hemoglobin's affinity for oxygen also increases, allowing for more oxygen to be loaded. Conversely, as the partial pressure decreases, oxygen is unloaded from hemoglobin.

**Hint:** Think about how changes in pO2 affect hemoglobin saturation and the physiological implications of this relationship.

### Step 5: Conclusion
Based on the analysis, the correct answer to the question is the **O2 dissociation curve**. This curve effectively illustrates how oxygen is loaded onto and unloaded from hemoglobin in response to changes in the partial pressure of oxygen.

**Final Answer:** The curve that shows how oxygen is loaded and unloaded due to partial pressure is the **O2 dissociation curve**.